The invention relates to the use of a thermal detecting device to detect standing waves in a tire.
In the development of a tire, many tools are used to confirm the viability of proposed tire constructions before new constructions or designs are committed to production. One such tool is the detection of standing waves in a tire. Standing waves are sinusoidal in nature, and are an indication of the expenditure of energy and stresses placed on a tire being focused on certain locations in the tire. Standing waves develop at certain speeds or inflations as the tire is tested and may fluctuate between severe and non-severe amplitudes depending on the testing speeds. In the prior art, the method to detect standing waves comprised the use of moire images, i.e., images created using interferometry. In the prior art, such waves are detected at speeds between 90 and 105 miles per hour, and until the present invention, it was believed that these standing waves did not form until these speeds were achieved. Accordingly, in evaluating a tire construction or design, preliminary testing on new designs sometimes included high speed testing for the purpose of creating shadow moire images.
The detection of the standing waves, the speed at which they occur, and their severity, are information used by the tire designer in modifying his design to reduce or eliminate the problem. Standing waves may cause a tire to fail prematurely.
The high speed equipment needed in the creation of shadow moire images, and the equipment needed to analyze the shadow moire data are very sophisticated and expensive. Although it may be that shadow moire testing, to a certain extent, will always have value, there is the need in the art for alternative testing which may be less expensive and, if possible, produces data that may be more easily analyzed. Other methods may at least supplement the data that can be obtained from shadow moire images.
A method for detecting standing waves in a rotating tire comprises the steps of (a) using a thermal detecting device to obtain a temperature profile of a rotating tire, and (b) analyzing thermal patterns in the data. The method may include using hardware and software for automating data capture and analysis. In the illustrated embodiment, a high speed infrared camera was used for obtaining thermal images. It has been found that a thermal difference between the valley and the peak of a standing wave can be detected at 40 mph to 80 mph
It is an object of the present invention to provide an apparatus and method for detecting standing waves in a tire at relatively slow speeds.
Further objects of the invention will be apparent from the following description and claims.